Creating JSON with million records

composer.json

{
    "name": "aflangofas/json",
    "require": {
        "fzaninotto/faker": "^1.6"
    },
    "authors": [
        {
            "name": "Antonis Flangofas",
            "email": "antonisflags@gmail.com"
        }
    ]
}

import.php

<?php

$folder = 'output/';

$files = array_diff(scandir($folder), ['.', '..']);

foreach ($files as $file) {
    echo 'Importing ' . $file . PHP_EOL;
    $output = shell_exec('mongoimport --db test --collection users --jsonArray --file output/' . $file);
    echo $output . PHP_EOL;
}

json.php

<?php
require __DIR__ . '/vendor/autoload.php';

use Faker\Factory;

$iterations = isset($argv[1]) ? $argv[1] : 5;
$entries = isset($argv[2]) ? $argv[2] : 6000;

function convert($size)
{
    $unit=array('b','kb','mb','gb','tb','pb');
    return @round($size/pow(1024,($i=floor(log($size,1024)))),2).' '.$unit[$i];
}

function random_float ($min,$max) {
   return ($min+lcg_value()*(abs($max-$min)));
}


function array_rand_value($container = [])
{
    if (empty($container)) {
        return false;
    }
    $key = array_rand($container);
    return $container[$key];
};

function createEmails($num = 1)
{
    $faker = Factory::create();
    $emails = [];

    do {
        $emails[] = [
            'value' => $faker->email,
            'type' => array_rand_value(['personal', 'work'])
        ];
        $num --;
    } while ($num);

    return $emails;
}

function createPhoneNumbers($num = 1)
{
    $faker = Factory::create();
    $numbers = [];
    $default = true;

    do {
        $numbers[] = [
            'value' => $faker->phoneNumber(),
            'type' => array_rand_value(['personal', 'work']),
            'is_Default' => $default
        ];

        $num --;
        $default = false;
    } while ($num);

    return $numbers;
}


function createAddresses($num = 1)
{
    $faker = Factory::create();
    $addresses = [];

    do {
        $addresses[] = [
            'type' => array_rand_value(['work', 'home']),
            'address' => $faker->address(),
            'city' => $faker->city(),
            'zip' => $faker->postcode(),
            'country' => $faker->country(),
            'state' => $faker->stateAbbr()
        ];

        $num --;
    } while ($num);

    return $addresses;
}

function createResults($options)
{
    $faker = Factory::create();
    extract($options);

    $results = [
        "finalScore" => number_format(random_float(0.00, 10.00), 2, '.', ''),
        "dateSent"=> $serviceDate,
        "dateCompleted" => $serviceDate,
        "surveyDetails" => [
            "On a scale of 0-10, please rate your level of satisfaction with your service(s) (with 10 being the highest level of satisfaction):" => rand(0,10),
            "What is the likelihood that you would suggest Vein Clinics of America to a friend or family member interested in similar services? (10 being the greatest likelihood):" => rand(0,10),
            "The Office Staff: The Scheduling Process was Easy and Convenient" => array_rand_value(['Disagree Strongly', 'Disagree', 'Neutral', 'Agree', 'Agree Strongly']),
            "The Office Staff: Your Greeting and Send-Off were Warm and Professionalt" => array_rand_value(['Disagree Strongly', 'Disagree', 'Neutral', 'Agree', 'Agree Strongly']),
            "The Office Staff: Your Wait was Brief and Comfortable" => array_rand_value(['Disagree Strongly', 'Disagree', 'Neutral', 'Agree', 'Agree Strongly']),
            "The Office Staff: The Payment Process was Easy and Convenient" => array_rand_value(['Disagree Strongly', 'Disagree', 'Neutral', 'Agree', 'Agree Strongly']),
            "What factors were most important in choosing this location for your procedure? (choose any that apply)" => array_rand_value(["Confidence that I would get great results","Positive Consultation Experience","Staff Expertise","Travel (Distance)"]),
            "Getting to Know You: For the next few questions, please choose the answer that accurately describes you, starting with Gender:" => array_rand_value(['male', 'female', 'prefer not to say'])
        ]
    ];
    $emptyChance = rand(0, 4);
    if (!$emptyChance) {
        return [];
    }

    return $results;
}

function createEvents($num = 50, $options = [])
{
    $events = [];
    $faker = Factory::create();
    $serviceDate = $faker->dateTimeBetween('-3 years', 'now');
    // $completedDate = $serviceDate->add(new DateInterval('P10D'))->format('Y-m-d');
    $serviceDate = $serviceDate->format('Y-m-d');
    $cId = intval( "0" . rand(1,9) . rand(0,9) . rand(0,9) . rand(0,9) . rand(0,9) . rand(0,9) . rand(0,9));
    extract($options);

    do {
        $events[] = [
            'clientBrandID' => $id,
            'surveyType' =>  array_rand_value([5005, 5004, 5003, 5002, 5001]),
            'location'=> $city,
            'clientContactID' => $cId,
            "firstName" => $firstname,
            "lastName" => $lastname,
            "birthDate" => $dob,
            "email" => $email['value'],
            "address" => $address,
            "city" => $city,
            "state" => $state,
            "zip" => $zip,
            "consultDate" => "",
            "consultantName" => "",
            "consultServiceType" => "",
            "serviceDate" => 2,
            "serviceProviderName" => "Carolyn Thas, RN",
            "serviceType" => array_rand_value(['MVD', 'DVM', 'MDV', 'DVMM', 'MMM']),
            "consultCancellationDate" => "",
            "serviceRevenue" => number_format(random_float(0.00,20000.00), 2, '.', ''),
            "userVarChar4" => "Insurance",
            "leadSource" => array_rand_value(['DTC', 'Phone', 'Website', 'Social Media', 'Other']),
            "results" => createResults(array_merge($options, ['serviceDate' => $serviceDate]))
        ];

        $num --;
    } while ($num);

    return $events;
}

function createClients($options)
{
    global $dob, $email;
    $result = [];
    $clientIds = [35, 67, 73, 78, 82];
    $clientIds = array_slice($clientIds, rand(0, count($clientIds) - 1), count($clientIds));
    extract($options);
    foreach ($clientIds as $id) {
        $result[] = [
            'clientId' => $id,
            'mainInfo' => [
              "firstName" => $firstname,
              "lastName" => $lastname,
              "birthDate" => $dob,
              "email" => $email['value'],
              "address" => $address,
              "city" => $city,
              "state" => $state,
              "zip" => $zip,
            ],
            'events' => createEvents(rand(1,5), array_merge($options, ['dob' => $dob, 'email' => $email, 'id' => $id]))
        ];
    }

    return $result;
}

$faker = Factory::create();
$c = [];
for ($y = 1; $y <= $iterations; $y++) {
    for ($i = 0; $i < $entries; $i++) {
        //survey taker
        $firstname = $faker->firstName;
        $lastname = $faker->lastName;
        $dob = $faker->dateTimeThisCentury->format('Y-m-d');
        $emails = createEmails(rand(1,2));
        $email = $emails[0];
        $addresses = createAddresses(rand(1,2));
        $contact = $addresses[0];
        $options = array_merge($contact, ['firstname' => $firstname, 'lastname' => $lastname, 'email' => $email]);
        extract($contact);

        $container = [
            'name' => [
                'firstname' => $firstname,
                'lastname' => $lastname,
            ],
            'emails' => $emails,
            'phoneNumbers' => createPhoneNumbers(rand(1,2)),
            'addresses' => $addresses,
            'dob' => $dob,
            'clients' => createClients($options)
        ];
        $c[] = $container;
    }
    echo "Batch " . $y . PHP_EOL;
    echo "Memory usage " . convert(memory_get_usage(true)) . PHP_EOL;
    $fileName = 'user-dataset-' . $y . '.json';
    file_put_contents('output/' . $fileName, json_encode($c), JSON_PRETTY_PRINT);
    $container = $firstname = $contact = $emails = $addresses = $fileName = $c = null;
}